New York/Paris: Facebook Inc. chief executive officer Mark Zuckerberg said it will take “a few years" to solve the issues plaguing the social media company.

“I wish I could solve all these issues in three months or six months, but I just think the reality is that solving some of these questions is just going to take a longer period of time," he said in a podcast interview with media publication Vox.

The company started investing more in security at least a year ago, Zuckerberg said,“so if this is going to be a three-year process, then I think we’re about a year in already. Hopefully by the end of this year, we’ll have really started to turn the corner on some of these issues."

Zuckerberg is trying to steer Facebook through one of its worst public crises, after revelations that Cambridge Analytica, a political consulting firm that worked on US President Donald Trump’s election campaign, obtained the private data of some 50 million Facebook users. Facebook’s shares have dropped about 14% since the news emerged and Zuckerberg has been called to testify before Congress in coming weeks. Politicians in the UK and the European Union have also requested Zuckerberg to come explain how Facebook protects the privacy of its 2 billion monthly users, and Missouri’s attorney general announced Monday that he is launching a wide-ranging probe into Facebook.

Facebook shares were down 1.4% in pre-market trading in New York to $157.50.

In the Vox interview, Zuckerberg defended Facebook’s advertising-driven business model, saying that it wasn’t incompatible with serving people. He argues that building a service that connects people everywhere has to be available to everyone, and not all people would be able to pay otherwise.

“I don’t think at all that that means that we don’t care about people," Zuckerberg said. “I think to the contrary."

Before the Cambridge Analytica revelations, Facebook was already under heightened scrutiny, along with other social media companies, for failing to crack down on Russian meddling in the 2016 presidential election. Zuckerberg said working on foreign intervention was going to be a “huge focus for us going forward." Facebook has about 14,000 people working on security and community operations, he said.

This year will be a “big year for us for elections around the world," he said, including midterm elections in the US, India, Brazil, Mexico and elsewhere.

In the interview, Zuckerberg also responded to criticism from Apple Inc. CEO Tim Cook about the company’s business model. Zuckerberg described Cook’s assessment that Apple has a more solid model because it sells products to users, rather than selling users to advertisers, as “extremely glib, and not at all aligned with the truth." Bloomberg